SUMAC JFAMILY. 137 
The plant is a perennial shrub, sometimes low and 
erect and sometimes trailing or climbing by aerial root- 
The Plant lets. The leaves are petioled, and pinnately 
compound, with three irregularly ovate leat- 
lets, variously notched and toothed. Scarcely two leaves 
on the same or different plants can be found alike, and this 
proves a most valuable means for identification. The 
inconspicuous flowers grow in loose panicles in the axils 
of the leaves. The fruit is whitish and globular, with a 
waxy appearance. ‘ 
Whenever practicable, Poison Ivy should be eradicated. 
Where possible it is best to plow the land where it grows 
and crop it until the ivy is killed. For places where this 
cannot be done, Stone recommends a solution of one-half 
to one pound of arsenate of soda dissolved in five gallons 
of water. This should be applied in sufficient quantity 
to soak into the soil and reach the roots. Five gallons is 
sufficient to treat three to five square rods. 
WESTERN POISON Ivy OR POISON OAK, Rhus Rydbergi 
Small, a low shrub growing in the Rocky Mountain re- 
gion, has the same effect as Rhus Toxicodendron. Unlike 
the latter, it does not creep or climb, but always stands 
erect, one to two feet high. The three leaflets are often 
tinged with purple when young. The small, greenish 
flowers are borne as in the eastern Poison Ivy, and the 
shiny white fruit is similar. 
POISON OR SWAMP SuUMAC, Rhus Vernix L., is a shrub 
or small tree sometimes attaining a height of twenty-five 
feet. It is found in the eastern and central United States 
and in Ontario, and produces effects similar to those of 
Poison Ivy. The leaves are petioled and pinnately com- 
